1. Field of the Invention
The present invention relates generally to systems for controlling copying machines, and more specifically, to a system for controlling at a control center, copying machines each having a corresponding copying machine control unit, in which a centralized control apparatus at the control center is called by each copying machine control unit through a communication line when prescribed conditions are satisfied and data communication is established between the copying machine control unit and the centralized control apparatus.
2. Description of the Related Art
A system for controlling a plurality of copying machines is disclosed in U.S. Pat. No. 4,583,834. In the disclosed system, various kinds of information on a copying machine such as the total number of sheets copied, problems, the remaining amounts of copy sheets and toner are transmitted to a computer. The computer processes the transmitted information and feeds back instructions to the copying machine.
According to such a system, remote control of a plurality of copying machines supplied to users can be made by connecting those plurality of copying machines with a centralized control apparatus through a communication network such as a telephone line. The centralized control apparatus is provided at the site of an administrator, and the administrator receives information transmitted from each copying machine by the use of the centralized control apparatus. Various administrative works are conducted such as issue of bills based on the number of copy sheets, and dispatch of serviceman to cope with problems.
A general copying machine does not have a function of communicating with a centralized control apparatus through a communication network, and, therefore, a data terminal for communication is provided for the copying machine when such a system is constructed. The data terminal collects various kinds of information from the copying machine and communicates with the centralized control apparatus based on the collected information.
From the viewpoint of the administrator of copying machines, when the data terminal provided for a copying machine is in trouble, it is preferable to prohibit the operation of the copying machine. More specifically, it is desirable for the administrator to prohibit the use of a copying machine which is not under the control of the system when the data terminal is in trouble. From the viewpoint of users, however, it would be unreasonable if the operation of a normal copying machine is prohibited because of the problems in the data terminal. Accordingly, it would be desirable to continue the operation of the copying machine regardless of the trouble in the data terminal.
Meanwhile, it is simply enough to control the state of transmission from the data terminal at the site of centralized control apparatus, in order to detect a problems associated with the data terminal. In other words, a data terminal which does not make a transmission can be determined to be faulty. However, increasing the number of transmissions from a data terminal to the centralized control unit thoughtlessly for the purpose of detecting a problems taking place in the data terminal at an early stage should be avoided, considering the cost involved.